The rumor that the Republican Party has a tape of Michelle Obama railing against "whitey" in Rev. Jeremiah Wright's church apparently surfaced two weeks ago on No Quarter, a blog operated by Larry Johnson, a self-described former CIA analyst and supporter of Obama's Democratic presidential rival Hillary Clinton. No evidence has emerged to corroborate the wild rumor, but Fox News went ahead and aired the charges on camera today. The justification?

To get the perspective of admitted political smear artist Roger Stone. In a neat demonstration of the media echo chamber, Stone said he hadn't heard of the purported video, but now believes it exists because so many TV news networks have called to ask him about it.

Host Geraldo Rivera said he'd bet $100 against the rumor being true, but it doesn't matter: If the Republicans can keep everyone talking about the rumor through October, when Johnson's "Republican sources" say it will surface, the chatter will have, in and of itself, hurt Obama in the same significant way spurious rumors about him being Islamic delivered votes to Clinton.

That right-wing, Roger Ailes-operated Fox News is helping to facilitate this damage via national television should come as no surprise; the real test is whether the other networks will now follow suit and further whip up this corrosive, baseless rumor, simply because there's nothing else they want to talk about.